As always, it’s more a matter of how and why people want to use their GPS devices.
Some, like me, want to plot their own routes from A to D, via B and C. Though I am not beyond using third party sourced routes, too. For my purposes, BaseCamp and / or Mapsource work perfectly well. Similarly, all my Garmin / BMW branded GPS devices have worked pretty well too, once I understood them. That understanding took effort, often through making mistakes and through finding out why something happened. This forum and the internet has been useful in helping that learning process along.
Others, do not want to do any plotting at all. They just want to ask their GPS device to take them from A to D (maybe via B and C) and are not fussed how it does it, providing it does not take them along motorways, or into the middle of towns that they have chosen and (sometimes) providing it does not route them along a goat track that you wouldn’t take a horse along. These people do not need BaseCamp, Mapsource or any other route plotting software. They don’t even need a home computer, other than to maybe update a map. Now that some devices allow for wireless updating and the transfer of routes via Bluetooth, their need for a PC is almost reduced to zero.
Somewhere between the two float the people who want to plot their own routes but outside of Garmin’s generic two route plotting pieces of software, Mapsource and BaseCamp. It’s often them that struggle most, encountering the glitches and foibles that come from mixing two or more different systems together.
Into this happy mixture lob, preference settings, route avoidances, detours, automatic recalculation, road closures, petrol stations that are shown on a map but have gone, roads that are not shown on the map, prompted recalculation and no recalculation, waypoints and shaping points, the sun shining on the screen and mates who say “YOU are going wrong, as MY device says....” and you have an unholy mess.
Then, right on the outside are those that refuse to learn how their expensive and now very powerful GPS devices work, so used are they to plug and play. That they’ll not have a map as a back-up and not the slightest idea of where they are, how they got there or where they are going, is just a bonus. But nobody really cares about them.